The goal of this study is to test the hypothesis that alprazolam is detectable in hair samples and is correlated with plasma and whole blood concentrations. Unconjugated alprazolam and a-hydroxyalprazolam in plasma, whole blood, urine and hair will be analyzed by gas chromatography and mass spectrometry. These data will be used to determine the length of time required for the drug to appear in hair, concentration, dose-response relationship, gender differences in hair concentrations, and the effects of hair washing on drug concentration.